1 files changed, 417 insertions, 0 deletions
diff --git a/src/net/splice_test.go b/src/net/splice_test.go
new file mode 100644
index 0000000..fa14c95
--- /dev/null
+++ b/src/net/splice_test.go
@@ -0,0 +1,417 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux
+
+package net
+
+import (
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"strconv"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestSplice(t *testing.T) {
+	t.Run("tcp-to-tcp", func(t *testing.T) { testSplice(t, "tcp", "tcp") })
+	if !testableNetwork("unixgram") {
+		t.Skip("skipping unix-to-tcp tests")
+	}
+	t.Run("unix-to-tcp", func(t *testing.T) { testSplice(t, "unix", "tcp") })
+	t.Run("no-unixpacket", testSpliceNoUnixpacket)
+	t.Run("no-unixgram", testSpliceNoUnixgram)
+}
+
+func testSplice(t *testing.T, upNet, downNet string) {
+	t.Run("simple", spliceTestCase{upNet, downNet, 128, 128, 0}.test)
+	t.Run("multipleWrite", spliceTestCase{upNet, downNet, 4096, 1 << 20, 0}.test)
+	t.Run("big", spliceTestCase{upNet, downNet, 5 << 20, 1 << 30, 0}.test)
+	t.Run("honorsLimitedReader", spliceTestCase{upNet, downNet, 4096, 1 << 20, 1 << 10}.test)
+	t.Run("updatesLimitedReaderN", spliceTestCase{upNet, downNet, 1024, 4096, 4096 + 100}.test)
+	t.Run("limitedReaderAtLimit", spliceTestCase{upNet, downNet, 32, 128, 128}.test)
+	t.Run("readerAtEOF", func(t *testing.T) { testSpliceReaderAtEOF(t, upNet, downNet) })
+	t.Run("issue25985", func(t *testing.T) { testSpliceIssue25985(t, upNet, downNet) })
+}
+
+type spliceTestCase struct {
+	upNet, downNet string
+
+	chunkSize, totalSize int
+	limitReadSize        int
+}
+
+func (tc spliceTestCase) test(t *testing.T) {
+	clientUp, serverUp := spliceTestSocketPair(t, tc.upNet)
+	defer serverUp.Close()
+	cleanup, err := startSpliceClient(clientUp, "w", tc.chunkSize, tc.totalSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cleanup()
+	clientDown, serverDown := spliceTestSocketPair(t, tc.downNet)
+	defer serverDown.Close()
+	cleanup, err = startSpliceClient(clientDown, "r", tc.chunkSize, tc.totalSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cleanup()
+	var (
+		r    io.Reader = serverUp
+		size           = tc.totalSize
+	)
+	if tc.limitReadSize > 0 {
+		if tc.limitReadSize < size {
+			size = tc.limitReadSize
+		}
+
+		r = &io.LimitedReader{
+			N: int64(tc.limitReadSize),
+			R: serverUp,
+		}
+		defer serverUp.Close()
+	}
+	n, err := io.Copy(serverDown, r)
+	serverDown.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := int64(size); want != n {
+		t.Errorf("want %d bytes spliced, got %d", want, n)
+	}
+
+	if tc.limitReadSize > 0 {
+		wantN := 0
+		if tc.limitReadSize > size {
+			wantN = tc.limitReadSize - size
+		}
+
+		if n := r.(*io.LimitedReader).N; n != int64(wantN) {
+			t.Errorf("r.N = %d, want %d", n, wantN)
+		}
+	}
+}
+
+func testSpliceReaderAtEOF(t *testing.T, upNet, downNet string) {
+	clientUp, serverUp := spliceTestSocketPair(t, upNet)
+	defer clientUp.Close()
+	clientDown, serverDown := spliceTestSocketPair(t, downNet)
+	defer clientDown.Close()
+
+	serverUp.Close()
+
+	// We'd like to call net.splice here and check the handled return
+	// value, but we disable splice on old Linux kernels.
+	//
+	// In that case, poll.Splice and net.splice return a non-nil error
+	// and handled == false. We'd ideally like to see handled == true
+	// because the source reader is at EOF, but if we're running on an old
+	// kernel, and splice is disabled, we won't see EOF from net.splice,
+	// because we won't touch the reader at all.
+	//
+	// Trying to untangle the errors from net.splice and match them
+	// against the errors created by the poll package would be brittle,
+	// so this is a higher level test.
+	//
+	// The following ReadFrom should return immediately, regardless of
+	// whether splice is disabled or not. The other side should then
+	// get a goodbye signal. Test for the goodbye signal.
+	msg := "bye"
+	go func() {
+		serverDown.(io.ReaderFrom).ReadFrom(serverUp)
+		io.WriteString(serverDown, msg)
+		serverDown.Close()
+	}()
+
+	buf := make([]byte, 3)
+	_, err := io.ReadFull(clientDown, buf)
+	if err != nil {
+		t.Errorf("clientDown: %v", err)
+	}
+	if string(buf) != msg {
+		t.Errorf("clientDown got %q, want %q", buf, msg)
+	}
+}
+
+func testSpliceIssue25985(t *testing.T, upNet, downNet string) {
+	front := newLocalListener(t, upNet)
+	defer front.Close()
+	back := newLocalListener(t, downNet)
+	defer back.Close()
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+
+	proxy := func() {
+		src, err := front.Accept()
+		if err != nil {
+			return
+		}
+		dst, err := Dial(downNet, back.Addr().String())
+		if err != nil {
+			return
+		}
+		defer dst.Close()
+		defer src.Close()
+		go func() {
+			io.Copy(src, dst)
+			wg.Done()
+		}()
+		go func() {
+			io.Copy(dst, src)
+			wg.Done()
+		}()
+	}
+
+	go proxy()
+
+	toFront, err := Dial(upNet, front.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	io.WriteString(toFront, "foo")
+	toFront.Close()
+
+	fromProxy, err := back.Accept()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer fromProxy.Close()
+
+	_, err = io.ReadAll(fromProxy)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	wg.Wait()
+}
+
+func testSpliceNoUnixpacket(t *testing.T) {
+	clientUp, serverUp := spliceTestSocketPair(t, "unixpacket")
+	defer clientUp.Close()
+	defer serverUp.Close()
+	clientDown, serverDown := spliceTestSocketPair(t, "tcp")
+	defer clientDown.Close()
+	defer serverDown.Close()
+	// If splice called poll.Splice here, we'd get err == syscall.EINVAL
+	// and handled == false.  If poll.Splice gets an EINVAL on the first
+	// try, it assumes the kernel it's running on doesn't support splice
+	// for unix sockets and returns handled == false. This works for our
+	// purposes by somewhat of an accident, but is not entirely correct.
+	//
+	// What we want is err == nil and handled == false, i.e. we never
+	// called poll.Splice, because we know the unix socket's network.
+	_, err, handled := splice(serverDown.(*TCPConn).fd, serverUp)
+	if err != nil || handled != false {
+		t.Fatalf("got err = %v, handled = %t, want nil error, handled == false", err, handled)
+	}
+}
+
+func testSpliceNoUnixgram(t *testing.T) {
+	addr, err := ResolveUnixAddr("unixgram", testUnixAddr(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(addr.Name)
+	up, err := ListenUnixgram("unixgram", addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer up.Close()
+	clientDown, serverDown := spliceTestSocketPair(t, "tcp")
+	defer clientDown.Close()
+	defer serverDown.Close()
+	// Analogous to testSpliceNoUnixpacket.
+	_, err, handled := splice(serverDown.(*TCPConn).fd, up)
+	if err != nil || handled != false {
+		t.Fatalf("got err = %v, handled = %t, want nil error, handled == false", err, handled)
+	}
+}
+
+func BenchmarkSplice(b *testing.B) {
+	testHookUninstaller.Do(uninstallTestHooks)
+
+	b.Run("tcp-to-tcp", func(b *testing.B) { benchSplice(b, "tcp", "tcp") })
+	b.Run("unix-to-tcp", func(b *testing.B) { benchSplice(b, "unix", "tcp") })
+}
+
+func benchSplice(b *testing.B, upNet, downNet string) {
+	for i := 0; i <= 10; i++ {
+		chunkSize := 1 << uint(i+10)
+		tc := spliceTestCase{
+			upNet:     upNet,
+			downNet:   downNet,
+			chunkSize: chunkSize,
+		}
+
+		b.Run(strconv.Itoa(chunkSize), tc.bench)
+	}
+}
+
+func (tc spliceTestCase) bench(b *testing.B) {
+	// To benchmark the genericReadFrom code path, set this to false.
+	useSplice := true
+
+	clientUp, serverUp := spliceTestSocketPair(b, tc.upNet)
+	defer serverUp.Close()
+
+	cleanup, err := startSpliceClient(clientUp, "w", tc.chunkSize, tc.chunkSize*b.N)
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer cleanup()
+
+	clientDown, serverDown := spliceTestSocketPair(b, tc.downNet)
+	defer serverDown.Close()
+
+	cleanup, err = startSpliceClient(clientDown, "r", tc.chunkSize, tc.chunkSize*b.N)
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer cleanup()
+
+	b.SetBytes(int64(tc.chunkSize))
+	b.ResetTimer()
+
+	if useSplice {
+		_, err := io.Copy(serverDown, serverUp)
+		if err != nil {
+			b.Fatal(err)
+		}
+	} else {
+		type onlyReader struct {
+			io.Reader
+		}
+		_, err := io.Copy(serverDown, onlyReader{serverUp})
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func spliceTestSocketPair(t testing.TB, net string) (client, server Conn) {
+	t.Helper()
+	ln := newLocalListener(t, net)
+	defer ln.Close()
+	var cerr, serr error
+	acceptDone := make(chan struct{})
+	go func() {
+		server, serr = ln.Accept()
+		acceptDone <- struct{}{}
+	}()
+	client, cerr = Dial(ln.Addr().Network(), ln.Addr().String())
+	<-acceptDone
+	if cerr != nil {
+		if server != nil {
+			server.Close()
+		}
+		t.Fatal(cerr)
+	}
+	if serr != nil {
+		if client != nil {
+			client.Close()
+		}
+		t.Fatal(serr)
+	}
+	return client, server
+}
+
+func startSpliceClient(conn Conn, op string, chunkSize, totalSize int) (func(), error) {
+	f, err := conn.(interface{ File() (*os.File, error) }).File()
+	if err != nil {
+		return nil, err
+	}
+
+	cmd := exec.Command(os.Args[0], os.Args[1:]...)
+	cmd.Env = []string{
+		"GO_NET_TEST_SPLICE=1",
+		"GO_NET_TEST_SPLICE_OP=" + op,
+		"GO_NET_TEST_SPLICE_CHUNK_SIZE=" + strconv.Itoa(chunkSize),
+		"GO_NET_TEST_SPLICE_TOTAL_SIZE=" + strconv.Itoa(totalSize),
+		"TMPDIR=" + os.Getenv("TMPDIR"),
+	}
+	cmd.ExtraFiles = append(cmd.ExtraFiles, f)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+
+	donec := make(chan struct{})
+	go func() {
+		cmd.Wait()
+		conn.Close()
+		f.Close()
+		close(donec)
+	}()
+
+	return func() {
+		select {
+		case <-donec:
+		case <-time.After(5 * time.Second):
+			log.Printf("killing splice client after 5 second shutdown timeout")
+			cmd.Process.Kill()
+			select {
+			case <-donec:
+			case <-time.After(5 * time.Second):
+				log.Printf("splice client didn't die after 10 seconds")
+			}
+		}
+	}, nil
+}
+
+func init() {
+	if os.Getenv("GO_NET_TEST_SPLICE") == "" {
+		return
+	}
+	defer os.Exit(0)
+
+	f := os.NewFile(uintptr(3), "splice-test-conn")
+	defer f.Close()
+
+	conn, err := FileConn(f)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var chunkSize int
+	if chunkSize, err = strconv.Atoi(os.Getenv("GO_NET_TEST_SPLICE_CHUNK_SIZE")); err != nil {
+		log.Fatal(err)
+	}
+	buf := make([]byte, chunkSize)
+
+	var totalSize int
+	if totalSize, err = strconv.Atoi(os.Getenv("GO_NET_TEST_SPLICE_TOTAL_SIZE")); err != nil {
+		log.Fatal(err)
+	}
+
+	var fn func([]byte) (int, error)
+	switch op := os.Getenv("GO_NET_TEST_SPLICE_OP"); op {
+	case "r":
+		fn = conn.Read
+	case "w":
+		defer conn.Close()
+
+		fn = conn.Write
+	default:
+		log.Fatalf("unknown op %q", op)
+	}
+
+	var n int
+	for count := 0; count < totalSize; count += n {
+		if count+chunkSize > totalSize {
+			buf = buf[:totalSize-count]
+		}
+
+		var err error
+		if n, err = fn(buf); err != nil {
+			return
+		}
+	}
+}